Molding apparatus



April 30, 1940. H. w. RICHTER HOLDING APPARATUS Filed May 25, 1934 2 Sheets-Sheet l a 3 M F 1% 4 \\\\\\\\\\s A 9 4 m ,H F s m 7ZJ// //fl/////%/ 7%/////// F4 INVENTOR. HERMAN W RICHTER FIG. 4

' ATTORNEYS April so, 1940. 'H, w, RICHTER 2,198,634

HOLDING APPARATUS Filed May 25, 1934 2 Sheets-Sheet 2 INVENTOR. ZIERJVAN W. RICA 7BR BYMMW mum! ATTORNEYS Patented Apr. 30, 1940 UNITED STATES PATENT OFFICE 2,198,634 MOLDING ArrAnA'rUs Herman William Richter, Bridgewater, Mass.

Application May 25, 1934, Serial No. 727.

2 Claims.

This application is a continuation in part of application Serial No. 638,603 filed October 19, 1932. The disclosure and claims of said application are directed to a shoe heel molded from fi- 312118 pulp and to a method of making said ar- The present; invention relates to the production of molds for the manufacture of shoe heels from fibrous pulp and other plastic materials.

Heretofore, many attempts have been made to place the manufacture of molded shoe heels on a commercial basis. (Reference is had to true heels of the type exemplified by the wooden heel of commerce rather than by the so-called rubber ll heel, which is a "top-lift" rather than a true heel.) Many patents for molded heel compositions have been granted. Elaborate machines for molding heels, some of them marvels of ingenuity, have been devised; but the rock on which most of these ventures came to grief was the mold. In many cases it was a complicated aflair; and always it had to be machined from solid metal, a very expensive process. Heels of different heights and sizes required different a molds. The style problem still further increased the number of molds needed for production. It wasadiscouragingtasktoequipaplantwith even the molds for the most limited line of heels. When it is realized that styles change a rapi ly. the mold problem, viewed from the conventional angle, becomes a hopeless one, and this in large measure accounts for the fact that the wood heel still dominates the market. This is so, in spite of the fact that it should be possible to produce a satisfactory molded heel having many advantages, including lower cost, over the conventional wooden article.

A primary object of the invention is to provide a novel form of mold for heels which is relatively simple in construction and which can be mcglde economically and rapidly on a commercial s e.

Another object is to provide a mold which will readily discharge the molded article without danger of injury thereto.

In its very essence, the mold of the invention comprises two mating sections mounted for pivotal movement toward and away from each other, each section being provided with a complemental portion of a mold cavity, said mold cavity having a concave breast portion for the formation of the concave breast of the heel to be formed therein, said concave breast portion.

of the mold cavity being formed on the side of 6 the mold cavity which is adjacent the point of pivot of said two mating sections, the distance from said point of pivot to said concave breast portion of the mold cavity being less than the radius of curvature of said concave breast portion of the mold cavity.

In the preferred embodiment of the invention, the mold is in the form of a hollow shell provided with a lining having impressed therein the com tour of the mold cavity or matrix. The lining is preferably of a readily fusible metal or alloy 1. so that it can easily be sweated out or removed by the heat of an oxyacetylene blow torch. Such a lining can be easily replaced whenever deemed necessary or desirable by either a duplicate lining or by one having a mold cavity of different con.- 1| tour. Hence, the cost of making replacements or changes in the matrix of the mold is greatly decreased. Furthermore, it is possible by the use of a relatively small number of standard mold shells to produce a large variety of styles, shapes go and sizes of heels.

The invention will now be described in detail with the aid of the accompanying drawings,

wherein:

Figure 1 is a vertical cross-section through a :5 preferred embodiment of molding device and showing the plunger in its lowermost position;

Figure 2 is a perspective view of the foraminous or perforated bottom plate of the matrix;

Figure 3 is a vertical cross-sectional view of the 30 lower end of the plunger taken at right angles to that of Figure 1;

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 1;

Figure 5 is a view similar to Figure 4 but showa ing the mold in the process of being opened;

Figure 6 is a perspective view of the casting constituting one-half of the outer shell of the mold;

Figure 7 is a perspective view of the outer shell 0 of the mold in closed position together with the end plates used in closing the ends of the shell when it is used for molding the lining of the mold, the end plates being shown somewhat spaced from the ends of the shell for clearness of illustration; and

Figure 8 is a perspective view of the assembled mold shell, end plates ahd core in position for the pouring or casting of the mold lining.

Referring to the drawings in ater detail and particularly to Figures 1 to 5 thereof, the reference characters I and 2 designate the two mating sections of the outer shell of a clam shell type of mold hinged together by means of the hinge 3 and hinge pin 4. Each of the shell sections l and 2 may advantageously be U-shaped in cross-section with inner and outer rectangular corners. Each section of the mold shell is provided with a closely fitting lining as indicated at 5, 6. The two lining sections 5 and 6' are provided with complementary portions of a central cavity which consists of a lower or matrix portion "I and an upper or reservoir portion 8. The matrix 1 is in the form of the article to be molded .and is slightly larger than the article while the cross-section of the reservoir 8 is preferably similar to that of the top of the article to be molded in order to accommodate the plunger 9 which is of similar uniform cross-section. The junction 80 between the matrix 1 and the reservoir 8 forms a seat for the plunger 9 in its lowermost position at which point it has just completed its function of compacting the plastic material in the matrix. The bottom ll of the plunger is of a shape to impart the desired configuration to the top of the article being molded. In the case of a shoe heel, the bottom of the plunger may be of exactly the same shape as that of the heel seat of the shoe for which the heel is intended so that the shoe heel is formed with a dished or concaved upper portion. In this way I can obviate the use of the conventional rand.

It is to be noted at this point that the matrix or mold cavity 1 is provided with a concave breast portion for the formation of the breast portion of the heel to be molded, that the breast portion is formed on the side of the mold cavity which is adjacent the hinge 3 of the two mating sections i and 2, and that the distance from the point of pivot to the concave breast portion of the mold cavity is less than the radius of curvature of the concave breast portion of the mold cavity. It is also to be noted that the junctions of the mating sections of the mold lie in a plane which bisects and is normal to the breast portion of the mold cavity, and that each of tho complemental portions of the mold cavity corresponds to a vertical half of the heel to be molded.

The numeral l2 designates a foraminous or perforated plate of the matrix. I have found it unnecessary to provide perforations about the vertical faces of the mold cavity, for the perforations in the bottom plate are sumcient to allow the drainage of all the water that can be forced out of the plastic material during the compacting operation. Both the bottom ll of theplunger 9- and the upper surface of the foraminous plate I 2 may be provided with the cooperating projections or protuberances l3 and I4 respectively for a purpose to be later brought out.

The pulp reservoir of the mold may advantageously be of such capacity as to permit the introduction at one time of a quantity of plastic material which bears a definite predetermined ratio to the total amount of plastic material necessary to produce a heel of desired dry weight.

The ratio may well be 1:1 in which case it will be possible to introduce at one time a sufhcient quantity of plastic material to produce the entire heel blank. The necessary capacity in the case of a pulp' slurry depends upon a number of factors including the freeness of the pulp, its concentration and the amount of water which can drain through the foraminous'plate l2 during the time it takes to pour the entire molding charge into the mold cavity. The theoretical total height of the mold cavity to form a heel blank of twentythree grams dry weight before the subsequent impregnation disclosed in my prior application from a pulp slurry of one per cent concentration holes for thehinge pin drilled.

is about 44 inches, but due to the drainage through .the perforated plate l2, the actual height need only be about thirty inches. It is well to allow a small margin for possible variations in freeness of the pulp. It can be seen i from the foregoing that the weight of the dry .them, for such blanks are rather more easily deformed during removal from the mold and shrink to a somewhat greater extent during drying and induration.

.There are several ways in which the mold may 2 be made. The mold shell may be made by casting, forging or machining each section out of suitable metals or alloys such asiron or steel.

I prefer to cast the mold shells out of iron or steel; one shell pattern being'sumcient for the 2 production of all the mold shells in the establishment. A typical rough casting of one-half of this mold shell is shown in Figure 6. Machine work necessary to fit the rough castings for subsequent use are within the skill of a mechanic 3| and need not be described. The two machined halves of; the shell are clamped together and the With the insertion of the hinge pin 4, the mold shell is complete (see Figure 7). 3:

die cast each of the lining sections therein. An- 4 other way consists in casting or forging the lin- .ing sections roughly to shape and then machining; their cavity surfaces to the exact contour design desired. I, however, prefer the following technique as being less' laborious, less time consuming and much less expensive.

Stated in broad general; terms, my preferred technique consists in casting a section of the mold lining in situ in each of the mold shell sections.

More specifically I proceed as follows:

Plates l5 and I6 are made out of heavy gauge steel (3/ 16" or over) for the ends of the mold shell. These plates are shown in Figure 7. Each plate is provided with three series of holes, II to 20 inclusive; 2| to 24 inclusive; and 25 and 26. The series of holes II to 20 inclusive line upwith one of the mold shells, while the series 2| to 24 inclusive line up with the other mold shell. The holes 25 and 26 are on the vertical center line of the plate and are equally spaced from the horizontal center line. Produced in quantities, these plates are made and drilled by template which assures perfect uniformity. The ends of the mold shells are provided in any desired manner with the series of holes I'm to 200. inclusive and tern 21, which obviously must be -of such shape and size as to exactly fitinto the mold cavitlv of the finished mold. To produce this pattern,

I first fashion a wooden pattern-exactly similar to the plunger 9, which, as has been stated, serves 7| 2m to 240. inclusive to correspond with the two the mold shell as shown in Figure 8.

Referring more particularly to Figure 8 it will be noted that the cast-iron core 21 is secured by means of the two sets of screws 28, 29 and 30, 3| to the end plates I5 and I6, which end plates are in turn secured to one of the mold shell sections I. The other mold section 2 is swung out ofthe way. It is to be particularly noted that the holes 25 and 26 are so positioned in the end plates that the plane of the upper faces of the mold shell I exactly bisects the core 21 longitudinally. Into the space between the core.2'| and the mold shell I the metal for the lining is poured. The end plates I5 and I6 prevent the shells.

Ordinary Babbitt metal may be used for the lining and will give fair service in molding heels out of the material disclosed in my prior appli-- cation, but even better results, especially from.

the standpoint of wear, may be obtained by usingthe harder alloys. When a mold shows signs of wear or it is desired to change the contour of the mold cavity, it is a simple matter to sweat out the fusible metal by means of the oxy-acetylene torch. g

Retention of 'the liner may be promoted by slightly undercutting the mold shell, as is done in dentistry to promote the retention of fillings; or screws may be inserted at several points in the m 1d and the metal cast around them.

Fro the foregoing description it is evident that t e mold shell lends. itself -readily for use as a standardized piece of equipment that can, by suitably varying the character of its lining, be employed for the production of any type, style or size of heel. In equipping a factory for the. molding of heels by my improved technique; I provide a number of these mold shells.

In using the apparatus, the plunger 9 is raised out of the way and the molding charge is introduced into the inold cavity. Since it is possible to pour the slurry in the same manner and at the same rate each time, the necessary amount of slurry to producea heel of desired dry weight can be left to the judgment of the operator, but obviously suitable measuring devices may be used.

a After the entire charge has been introduced, the

plunger-is moved to its lowest position; i. e., the seat III thus compacting the pulp in the matrix During the molding operation the molding apparatus may be heated in any suitable manner, as

the molding operation has been completed, the mold is opened by moving the two mold sections I and 2 about the pivot or hinge 3. Finally the 'plunger is raised and the article removed. As

can be readily seen from an examination of Fisures 4 and 5, the distance from the pivot I to the breast of the heel is less than the radius of curvature of the heel'breast and the distance from the pivot 3 to the outer curved edge of the heel is greater than the radius of curvature'of the curved outer edge of the heel so that when the mold is opened by swinging the two mating mold members I and 2 outwardly, the mold immediately breaks away from the molded heel for instance by being inserted inan oven. when blank. Furthermore, as can be seen from Figure I 1, the article is clamped and held steady between the cooperating projections I3 and I4. Hence, the possibility of damaging the article during the opening of the mold is reduced to a minimum.

' The foregoing constitutes the essential and dis:

tinct thought of my invention, but it will be understoodthat the details thereof may be varied or combined with various other details'without V affecting the peculiar results obtained,

I claim: 1. Amold for concave breast shoe heels, sai mold comprising two mating sections mounted for pivotal movement toward and away from each other, each section being provided with a complemental portion of a mold cavity, said mold cavity having a concave breast portion for the formation of the concave breast of the heel to be formed therein, said concave breast portion of the mold cavity being formed on the side of the mold cavity which is adjacent the point of mold comprising two mating sections mountetL for pivotal movement toward and away from and being provided with a removable lining, the lining in each section being provided with a complemental portion of a mold cavity, said mold each other, each of said sections being hollow cavity having a concave breast portion for the formation of the concaye breast of the heel to be formed therein, said concave breast portion of the mold cavity being formed on the side 01" the mold cavity which is adjacent the point of pivot of said two mating sections, the distance from said point of pivot to said concave breast portion of the mold cavity being less than the radius of curvature of said concave breast portion of the mold cavity.

mm: RICH'I'ER. 

